Liquid containing polymer marker, use of a polymer marker as authentication tool, and method and device for detecting a polymer marker dissolved in a liquid

Abstract

The present invention relates to markers for liquids that can be used to authenticate the origin and genuineness of a liquid, preferably a bulk liquid such as fuel. For this purpose, the present invention teaches the use of a polymer capable of forming a semiconducting polymer particle (pdot) in the liquid in small amounts. The invention encompasses a liquid comprising a) a polymer that is capable of forming a semiconducting polymer particle (pdot), the concentration of the polymer being 10 ppm by weight or less, and b) an organic substance in an amount of 90% by weight or more. The invention furthermore envisages the use of such a polymer as an authenticating marker in a liquid, preferably a fuel, and a method for authenticating the genuineness and/or origin of a liquid comprising a polymer capable of forming a semiconducting polymer particle (pdot), comprising the steps i. concentrating, isolating and/or extracting the polymer capable of forming a semiconducting polymer particle (pdot); ii. aggregating the polymer or the polymer obtained in Step i. to form semiconducting polymer dots (pdots); iii. irradiating the formed pdots with electromagnetic radiation capable of exciting the pdots to emit electromagnetic radiation by fluorescence and/or phosphorescence, and iv. observing the electromagnetic radiation emitted in response to the exciting irradiation of step iii.

The invention claimed is: 
     
       1. A method for authenticating the genuineness and/or origin of a liquid comprising a polymer capable of forming a semiconducting polymer particle (pdot), comprising the steps
 i. concentrating, isolating and/or extracting a polymer capable of forming a semiconducting polymer particle (pdot); 
 ii. aggregating the polymer obtained in Step i. to form semiconducting polymer dots (pdots); 
 iii. irradiating the formed pdots with electromagnetic radiation capable of exciting the pdots to emit electromagnetic radiation by fluorescence and/or phosphorescence, and 
 iv. observing electromagnetic radiation emitted in response to the exciting irradiation of step iii, wherein if the observed electromagnetic radiation conforms to a parameter that is defined as indicative for the genuineness and/or origin of the liquid, a decision as to the authenticity and/or origin of the liquid is made. 
 
     
     
       2. The method according to  claim 1 , wherein the liquid is a fuel and wherein the concentration of the polymer capable of forming a semiconductor particle is equal to or less than 10 ppm by weight. 
     
     
       3. The method according to  claim 1 , wherein the method is implemented in a portable device. 
     
     
       4. The method according to  claim 1 , wherein the aggregation of the polymer to form pdots is performed by re-precipitation using water and a water-miscible organic solvent; or by mini-emulsion using two or more non-miscible solvents and a surfactant. 
     
     
       5. The method according to  claim 1 , which additionally comprises the following steps:
 iii.a. irradiating the polymer capable of forming a semiconducting polymer particles, or a solution containing it, with electromagnetic radiation capable of exciting the polymers to emit electromagnetic radiation by fluorescence and/or phosphorescence, and 
 iv.a. observing the electromagnetic radiation emitted in response to the exciting irradiation of step iii.a. 
 
     
     
       6. The method according to  claim 5 , which comprises further a step of comparing the electromagnetic radiation emitted by the polymer observed in step iv.a with the electromagnetic radiation emitted by the pdot observed in step iv. 
     
     
       7. The method according to  claim 5 , wherein the polymer irradiated in step iii.a is present in a liquid to be evaluated for its genuineness and/or origin, is present in a water-soluble solvent other than the liquid to be evaluated for its genuineness and/or origin, or is present undissolved on a supporting surface. 
     
     
       8. The method according to  claim 1 , wherein the polymer capable of forming a semiconducting polymer dot (pdot) contains a structural unit selected from structural units comprising a (9, 9, dioctyl-2,7-divinylenefluorenylene)-alt-co-(9,10-anthracene) moiety of formula (1) and structural units comprising a moiety of formula (102):